Fuel injection system



Nov. 28, 1967 R. o. DURHAM 3,354,876

FUEL INJECTION SYSTEM Filed oct. 2l' 1965 3 Sheets-Sheet 1 r /6 T Mwd34- vili-IMLQS J BMM@ NOV. 28, 1967 R, Q DURHAM FUEL INJECTION SYSTEM 3Sheets-Sheet 2 Filed OCL. 2l. 1965 1 f m 5 3 1 w u M f 2 w il .2o J 5 I.2 1| P. .2 M 4 /ow a Z fw ,a 9 53 6 .5 Z 5 5 M lh l 09 M Ww q, 5 .I i M0--7 4. 7g o mw 5 rmeuegl.

Nov. 28, 1967 R. o. DURHAM 3,354,876

FUEL INJECTION SYSTEM Filed oct. 21, 1965 z sheets-sheet z Ivrea/rb?$05599 0. ,yam/,444,

United States Patent() 3,354,876 FUEL INJECTION SYSTEM Roger @.Durharn,3966 Marathon St., Los Angeles, Calif. 90029 Filed Oct. 21, 1965, Ser.No. 499,451 7 Claims. (Cl. 123-140) ABSTRACT F THE DISCLOSURE A fuelinjection system for internal combustion engines having a diaphragm typepump the pumping action of which is made dependent on the operatingspeed of the internal combustion engine and the air pressure in the airintake manifold of the engine. A lever type transmissionl or linkageoperates the pump diaphragm in response to rotary motion of the enginecrankshaft. A pressure sensitive unit is connected'between the airintake manifold and lever type linkage and causesthe linkage action, andthereby the diaphragm pumping action, to be dependent on air intakemanifold pressure.

The present invention relates to a fuel pumping system. Morevparticularly, the present invention relates to a fuel injection systemfor internal combustion engines in which the quantity of fuel pumped tothe engine is made dependent on engine speed and on the air pressurewithin the intake manifold of the engine.

While the use of intake manifold pressure to control the quantity offuel pumped to the engine is not unique, those fuel injection systemspreviously designedV to 'operate on this principle have generally beenquite complex and costly. As a consequence, very little use is made ofsuch fuel injection today, in spite of its well known advantages overthe more commonly used carburetion approach to precombustion mixing offuel and air. Y f d Therefore, one of the primary objects of the presentinvention is to provide a simple and inexpensive fuel injection system.Other and more specic objectives will become apparent from thedescription of the structure of the 'invention and its operation. v

Referring now to the drawings, FIGURE 1 thereof is a plan view of apreferred embodiment of the apparatus, using the deviceofcross-sectioning to disclose the interior portions of the structure.Briefly, FIGURE 1 shows the apparatus to lbe comprised of a transmissionhousing containing a linkage mechanism, a pump housing 11 containing adiaphragm type fuel pump, and a sensor housing 12 containing a devicesensitive vto pressure in the engine intake manifold. Y Y

FIGURE 2 is also a cross-sectioned plan View, showing an alternateconfiguration of the present invention wherein the sensor housing 12ycontains a bellows device instead of a diaphragm as shown rinVFIGURE 1. FIGURE 3 is merely a plan view showing an alternateconfiguration for the linkage mechanism contained within thetransmission housing 10. And FIGURE 4 is a plan View in crosssectionshowing an alternate configuration inwhich the transmission housingltl'isV secured directly vto the crankcase of the engine, and wherein aportion of the linkage mechanism extends into the crankcase, all as willbe more fully described herein.y

Turning vnow to the preferred embodiment of the present inventiondisclosed in FIGURE l, it is to be understood that this invention isintended for use vwith the typical internal combustion engine having anair intake manifold, fuel pump, pistons, crankshaft and so forth. Theinternal combustion engine of the class described is well known, so noeffort has been madeto illustrate the same in any detail.

' In FIGURE 1, the air intake manifold of theengine is ICC illustratedschematically by a body designated by numeral 6. The fuel intake portionyof the engine is similarly illustrated by body 7 in FIGURE 1, shownpositioned to receive fuel as it is pumped from housing 11.

The fuel injection pump itself, as shown in FIGURE l, .is comprised of ahousing .11 having a fuel inlet port 13, a fuel outlet port 14, and apumping port 16. These three ports all enter onto a pumping chamber 15.The housing 11 is secured to transmission housing 10 by bolts 17. Thefuel inlet port 13 is threaded and has disposed therein a standard inletcheck valve 18 and O ring seal 19. The fuel outlet port 14 is alsothreaded and has disposed therein a standard outlet check valve 20 and Oring seal 21.

Therpumping mechanism of the fuel pump, or fuel injection pump, iscomprised of a diaphragm 22 positioned in the pumping port, a diaphragmclamp ring 23 against which the diaphragm 22 can seat atits periphery tobe sealed between the clamp ring and the housing 11, by securing actionof bolts 17. The clamp ring is vwasher shaped and in its center aretainer screw 24 is secured by washer 26 and nut 27 to the diaphragm sothat a force applied to the head of retainer screw will move thediaphragm inwardly into the pumping chamber, decreasing Vthe volume ofthe pumping chamber, and a force applied to the washer will move thediaphragm outward, increasing the volume of the pumping chamber. Aspring 28 is vcompressively positioned in the pumping chamber to actupon washer 26 as shown. The head of retainer screw 24 is of suchdimensions that, when diaphragm 22 has moved outwardly as far as clampring 23 permits, a small air space 29 exists between the transmissionhousing 10 and the head of retainer screw 24. This air space isintersected by an air passage 30 leading to the exterior of thehousings. The purpose of air space 29 and air passage 30 is to preventthe alternate compression and rarefaction of air between retainer screw24 and transmission housing ttl during pumping operations. y

The pump housing 11 also contains an air bleed passage 31, with screwtype plug 32, the purpose of which is to bleed off air from the pumpingchamber so that it can be completely filled with fuel at the onset offuel injection system operation.

The apparatus used to detect and respond to air pressure in the airintake manifold of the engine is contained in the sensor housing 12,which housing, like the pump housing 11, is secured to the transmissionhousing 10 by bolts (not shown). The sensor housing 12 contains asubstantially cylindrical chamber 33 having an inlet port 34 and an exitport 36. The inlet port 34 is threaded to re ceive a conduit connectedbetween the engine intake manifold and chamber 33 whereby -air pressure,or lack thereof, in the intake manifold is communicated to chamber 33. AA pressure sensitive rolling type diaphragm 37 is clamped at itsperiphery between two portions of housing 12 so as to be responsive topressure changes in chamber 33. A threaded rod 40 extends from thetransmission housing, through the exit port 36, and through thediaphragm 37, being connected to the diaphragm by washers 41, 42, springcentering washer 43, and nuts 44 and 46. In this preferred embodimentrod 40 is threaded its entire length and is made of a flexible materialsuch as nylon or Teflon. A spring 47 is compressively disposed inchamber 33 to act against diaphragm 37 and urge it against the exit port36 of the chamber. Consequently, if the intake manifold pressure,transmitted to chamber 33, is the same as the air pressure admitted bythe exit port 36, then the diaphragm will be positioned as shown in PIG-URE l by the action of the spring 47.

The ytransmission housing 10 has an opening 4S over which the sensorhousing 12 is secured. The transmission housing contains a rotatablymounted shaft 49 (supported by bearings not shown) which carries a cam50 as shown.

The shaft 49 in this preferred embodiment piotrudes outside of thetransmission housing at one end and has a pulley xed thereon (notshown). This pulley can then be connected to the crankshaft or pulley oriiywheel thereof by means of the usual V belt, just as other engineequipment is operated off the crankshaft, such as the typicalelectricity generator.

In FIGURE 1, the crankshaft is designated by numeral 5, and a pulleyshown positioned thereon is designated by the numeral 8. The pulley inturn is connected by belt 9 to the shaft 49 of transmission housing 10.

The transmission housing also contains two levers 51 and 52 mounted onsubstantially oppositely disposed fulcrums 53 and 54. The levers areparallel to each other and remain essentially so during operation. Asillustrated, the -rod 40, which is actually a fulcrum rod or member, ispositioned between the two levers and carries a fulcrum bearing orelement 56 threaded onto the rod. Thus, action of lever 51 istransmitted to lever 52 through fulcrum element 56, and the position offulcrum element 56 prescribes the movements of lever 52 in response tolever 51.

Lever 51 contains a cam follower 57 that is continually in contact withcam 50. Lever 52 contacts a pump operating element 58 slidably mountedin a bearing 59, which element 58 is in contact with the retainer screw24 and, thus, diaphragm 22 of the pump housing. The levers and fulcrumelement 56 act as the mechanism to convert rotary motion of cam 50 intomovement of pump operating element 58.

The lever 52 also has a guide slot 60 to guide fulcrum bearing 56, andtwo stop members or feet, one of which is shown and designated bynumeral 61, which stop members are disposed on opposite sides of guideslot 60. The follower 57 is provided with threads to be adjustable asshown. With the cam 50 at its nadir the cam follower is adjusted tocause levers S1 and 52 to be parallel. The height of stop members orfeet 61 is slightly greater than the diameter of fulcrum bearing S6 sothat when the two levers are parallel the feet 61 cause the fulcrumbearing S6 to be freed from contact with the levers. In this condition,the fulcrum bearing 56 is easily movable by diaphragm 37 located in thesensor housing. For easy adjustment of the cam follower 57, anadjustment entry 82 in housing 10 is provided, with -a closure plug 83,and an access hole 84 is positioned in lever 52 opposite the camfollower.

FIGURE 2 shows an alternate configuration of the present inventionwherein the sensor housing 12 contains an evacuated bellows 62 to beresponsive to intake manifold pressure admitted through port 63. Theport 64 through which flexible fulcrum rod 40 extends is made air tightby a seal 66. The levers in the transmission housing are shown withtheir fulcrums reversed from that of FIGURE 1, but this is merely by wayof illustrating another alternative.

FIGURE 3 illustrates the levers 51 and 52 turned 90 degrees to eachother. The purpose of this alternative configuration is to provide amore nearly linear relationship between the stroke or position of pumpoperating element 5S and the position of the fulcrum bearing 56, if suchlinear relationship is desired.

FIGURE 4 shows still another alternate to the apparatus of FIGURE 1. InFIGURE 4 the transmission housing 10 is secured directly to thecrankcase 67 of the engine. The cam 50 is placed directly on the enginecrankshaft 68, and the lever 51 extends into the crankcase to ride onthe cam. To adjust the levers 51 and 52 to be parallel when the nadir ofthe cam is contacting lever 51, the entire transmission housing can beraised or lowered on the side of the crankcase. An obvious way to dothis would be to provide housing 10 with slots (not shown) instead ofholes, through which the bolts securing housing |10 to the crankcasecould be positioned. Of course, another approach would be to have thefulcrums 53 `and 54 (of the levers) adjustable up and down. A variety ofstandard devices could be used for this purpose.

The structure of the invention having been explained, attention is nowdirected to its operation.

The preferred embodiment of FIGURE 1, as with most fuel injectionsystems, is preferably used with a fuel pump which pumps fuel from asource, such as a gas tank, to the inlet check valve on the pump housing11. When the engine is started and the crankshaft begins to rotate, theshaft 49 in the transmission housing 10 also rotates, being connectedthereto by the usual pulley and V belt, as previously described. As thecam 50 rotates with shaft 49, the lever 51 is caused to move back andforth, which motion is transmitted through fulcrum bearing 56 to lever52, and thence to translational motion of pump operating element 58. Thetranslational motion of element 58, combined with the opposing force ofspring 28, causes the diaphragm 22 to alternately decrease and thenincrease the volume of pumping chamber 15.

As the volume increases fuel is 4admitted by inlet check valve 18 and asthe volume is decreased fuel is expelled through outlet check valve 20to the engine for mixture with air and combustion in the pistonchambers. The quantity of fuel that is pumped to the engine each cycleof the diaphragm 22 depends of course on the amount of movement of thediaphragm. This movement is in turn controlled by the position offulcrum bearing 56 between levers 51 and 52.

When the throttle on the engine is closed, as in the typical and usualengine idling condition, the pressure within sensor housing chamber 33is low since the air intake manifold pressure is low, and the diaphragm37 is withdrawn into chamber 3 3, pulling fulcrum bearing 56 up to araised position where the stop members 61 govern the interaction betweenlevers 51 and 52. It is to be recalled that this is due to stop members61 being slightly higher than the diameter of fulcrum bearing 56. Inview of the function performed by stop members 61, it would not beinappropriate to refer to them as idle clearance feet or idle deliveryfeet.

As the engine throttle is opened, air intake manifold increases and thediaphragm 37 is pushed downward, pushing fulcrum bearing 56 downwardbetween levers 51 and S2. As can be readily seen, the position ofbearing 56 causes more fuel to be pumped by diaphragm 22 as it movesdownward between the two levers, until its downward progress is stoppedby the bottoming of sensor housing diaphragm 37. The'spring 47 in thesensor housing is chosen so that, for normal operating conditions, thefulcrum bearing 56 is fully extended when the intake manifold pressure,the pressure in chamber 33, approaches atmospheric pressure.

As the cam 50 rotates, the fulcrum bearing 56 is released from contactwith levers 51 and 52 as the cam nadir passes the cam follower 57 oflever 51, which release is due to the size of the stop members 61 andthe parallel position of the levers at this juncture in the cycle. Atthis time then, the fulcrum bearing 56 is free to move either up or downin response to even slight pressure changes in chamber 33, the intakemanifold pressure.

Thus the present invention provides a fuel injection system that is notonly simple but which is responsive to small changes in intake manifoldpressure.

It will be apparent that the unit will operate with the sensor housing12 removed because of the stop members, or idle delivery feet, 61. Thus,even with the engine running, the senor housing could be removed toadjust the full throttle open position, or full power position, offulcrum bearing S6 on rod 40.

It will also be apparent that the quantity of fuel pumped by diaphragm22 can be changed by changing the sizes of the clamp ring 23 andretainer screw 24. Such size changes will `change the envelope of thediaphragm. This means that the unit can be adapted to most engines, eventhough of different make and horsepower rating, by a relatively simpleparts change. Preferably, the clamp `ring 23 and retainer screw 24 areselected to create a freely idling engine with the sensor housingremoved. y

An ,alternate structural configuration that can be employed in thlisarea is to use a diaphragm 22 without any retainer screw or clamp ring.In this configuration, the diaphragm 2,2 is clamped or secured directlybetween the pump housing 11 and the transmission housing 10. The spring28 can be removed and replaced by a spring'outside the pumping -chamberacting on pump `operating element 58 to keep it in Contact with `lever52. The simplest way to do this is to provide element 58 with a head andplace the spring concentrically about element 58 and beneath the head.In this structural configuration element 58, actuated by lever 52,pushes diaphragm 22 into the pumping chamber during one-half of thepumping cycle, and the normal pressure provided at the inlet check valveforces the diaphragm out of the chamber during the other half ofthecycle. It is to be recalled that this invention is preferably used witha fuel pump to supplyv fuel to the inlet check valve under somepressure;

This alternate structure reduces the amountofmass that must be movedback and forth during pumping operations, and lends itself toapplications Where it is desired to employ a plurality of pumps in themost efiicient manner. The invention, of course, can employ a variety ofvariable displacement` pumps, andy is not limited to use of thepreferred embodiment structure disclosed by the drawings andspecification. y y

The alternate configuration shown in FIGURE 2 is intended for use wheregreat changes in Iatmospheric pressure are encountered, such as inaircraft. The sensor housing chamber 33 is sealed, by seal 66, so'thatthe intake manifold pressure is compared with a constant reference,i.e., the force or pressure exerted by the evacuated bellows 62. With aclosed throttle, the air intake pressure is low and the bellows isvfully expanded, extending fulcrum bearing 56 far downlbetween levers 51and 52. In this configuration the fulcrumsoflevers 51 and 52 arereversed fr-om rthat shown in FIGURE 1` so that engine idle occurs whenrod 40 is fully extended. As `the intake manifold pressure builds up dueto the opening f the throttle, the bellows contracts, fulcrum bearing 56rises, ,and more fuel is pumped by diaphragm 22. y

If a plot of the stroke of pump operating element 58 vs. fulcrum bearing56 position were made, it would not be quite a straight line, yor linearrelationship. This means that at middle throttle openings, `the enginewill get slightly less rich fuel mixture than at the full throttle andidle throttle settings. If this is considered a handi` cap, depending onthe engine, the use to which it is put, and other factors, alinearrelationship can be achieved by rotating the levers 51 and 52 ninetydegrees with regard to each other. This is illustrated in FIGURE 3.

As still another alternative, if it is desired to have the inventionoperate directly off the engine crankshaft, and avoid use of shaft 49 ofFIGURE l and the usual pulley and, V-belt, then the configurationillustrated in FIGURE 4 can be employed. Here the transmission housing10 is fastened directly to the engine crankcase, the cam 50 is disposedright on the crankshaft of the engine, and

lever 51 extends, into the crankcase to vride on cam 50v and be actuatedthereby. The parallel adjustment of levers 51 and 52 lat cam nadir, aspreviously explained, can be achieved a number of ways, such as bymoving transmission housing up or down, or by providing means foradjusting fulcrums 53 and 54 up and down.

Although specific embodiments of the present invention have beendescribed and illustrated, it is to be understood that the same are byway of illustration and example and that the invention is not limitedthereto, as

many variations will be readily apparent to those versed in the art andthe invention is to be given its broadest possible interpretation withinthe terms of the following claims:

1. A fuel pumping system for an internal combustion engine having'acrankshaft and anintake manifold, said system comprising a diaphragmtype fuel pump Vadapted for connection to an engine and having a pumpoperating element, a pressure sensitive apparatus adapted for connectionto the intake manifold of an internal cornbustion engine, said apparatushaving a diaphragm movable in response to intake manifold pressure and afulcrum rod contacting said diaphragm and movable thereby, a cam adaptedfor rotation in response to rotation ofa crankshaft ofan internalcombustion engine, a linkage means having two levers with substantiallyoppositely disposed fulcrums, said levers being disposedsubstantiallyparallel to each other, said fulcrum rod positioned betweensaid levers and by its position affecting the amount of movement thatactuation of one lever imposesupon the other, oneof said leverscontacting said cam to be actuated thereby and the other levercontacting said pump operating element, rotation of said cam causingmovement of said pump operatingelement to pump fuel to the engine, thequantity of fuel pumped by said fiel pump being controlled by theposition of said fulcrum rod between said levers, and at least one ofsaid levers having 'a stop member extending towards said other lever andbeing of such dimensions that said fulcrum rod is substantially freedfrom Contact with said levers for an interval corresponding to a portionof the rotation of'said cam, and said fulcrum rod during said intervalbeing freely movable by said diaphragm of said pressure sensitiveapparatus so that small changes in intake manifold 'pressure will affectthe position of said fulcrum rod;

v2. A fuel pumping system for an internal combustion engine having -acrankshaft and an intake manifold, said system comprising a diaphragmtype fuel pump connected to supply fuel to the engine and having a pumpoperating element, a pressure sensitive apparatus connected to theintake manifold of the engine, said apparatus having a diaphragm movablein response to intake manifold pressure, Va flexible rod connected atone end to said diaphragm and being movable thereby, a fulcrum elementbeing disposed onV said flexible rod, a cam adapted for rotation inresponse to rotation of the engine crankshaft, a linkage means havingtwo levers with substantially oppos-itely disposed fulcrurns, saidlevers being disposed substantially parallel to each other, said fulcrumelement being positioned between said levers and by its positionaffecting the amount of movement that actuation of one lever imposesupon the other, one of said levers contacting said cam to be actuatedthereby and thev other lever contacting said pump operating element foractuation thereof, rotation of said cam causing movement of said pumpoperating element to pump fuel to the engine, the quantity of fuelpumped by said fuel pump being controlled by the position of said ful-Crum element between said levers, and at least one of said-levers havinga stop member extending towards said other leverl and being of suchdimensions that said fulcrum rod is substantially freed from contactwith said levers for an interval corresponding to a portion of therotation of said cam, and said flexible rod during said interval beingfreely movable by saidv diaphragm of said pressure sensitive apparatusso that small changes in intake manifold pressure will affect theposition of said fulcrum element.

3. Structure as claimed in claim 2 wherein said pressure sensitiveapparatus comprises a housing having a substantially cylindrical chambertherein, said chamber having an inlet port connected to the intakemanifold of the engine, a diaphragm disposed across said chamber andmovably responsive to pressure in said intake mauifold, said chamberhaving an exit port, and said flexible rod being disposed through saidexit port and connected at one end to said diaphragm.

4. A fuel pumping system for an internal combustion engine having acrankshaft and an intake manifold, said system comprising a diaphragmtype fuel pump connected to supply fuel to the engine and having a pumpoperating element, a pressure sensitive unit having a housing and asubstantially cylindrical chamber therein, a substantially evacuatedbellows fixed within said chamber so as to expand and contracttherewithin in response to pressure changes, said chamber having a firstport connected to the intake manifold, said chamber having a secondport, a flexible rod disposed through said second port and fixed to saidbellows to be movable thereby, an air seal disposed about said rod insaid second port and providing an air tight seal in said second port,said rod hav-ing a fulcrum element disposed thereon exterior to saidhousing of said pressure sensitive unit, a cam adapted for rotation inresponse to rotation of the engine crankshaft, a linkage means havingtwo levers with substantially oppositely disposed fulcrums, said leversbeing disposed substantially parallel to each other, said fulcrumelement being positioned between said levers and by its positionaffecting the amount of movement that actuation of one lever imposesupon the other, one of said levers contacting said cam to be actuatedthereby and the other lever contacting said pump operating element foractuation thereof, rotation of said cam causing movement of said pumpoperating element to pump fuel to the engine, the quantity of fuelpumped by said fuel pump being controlled by the position of saidfulcrum element between said levers, and at least one of said levershaving a stop member extending towards said other lever and being ofsuch dimensions that said fulcrum element is substantially freed fromcontact with said levers for an interval corresponding to a portion ofthe rotation of said cam, and said rod and fulcrum element during saidinterval being freely movable by said bellows of said pressure sensitiveunit so that small changes in intake manifold pressure will affect thepos-ition of said fulcrum element.

5. A fuel pumping system in combination with an internal combustionengine having a crankcase, a crankshaft within said crankcase, and anair intake manifold, said system comprising a transmission housingsecured to said chankcase, a sensor housing fixed to said transmissionhousing, `and a pump housing fixed to said transmission housing, a-diaphragm type fuel pump being disposed within said pump housing, apump operating element disposed to contact and operate said diaphragmtype fuel pump and extending into the interior of said transmissionhousing, said sensor housing having a pressure sensitive apparatustherein connected externally of said sensor housing to the intakemanifold of the internal combustion engine, said apparatus having apressure sensitive element movable in response to intake manifoldpressure, a fulcrum member contacting said pressure sensitive elementand movable thereby, said fulcrum member extending into the interior ofsaid transmission housing, a cam disposed on the crankshaft of theengine and rotatable therewith, a linkage means within .saidtransmission housing, said linkage means having two levers withsubstantially oppositely disposed fulcrums, said levers being disposedsubstantially parallel to each other, said fulcrum member positionedbetween said levers and by its position affecting the amount of movementthat actuation of one lever imposes upon the other, one of said leversextending into said crankcase and contacting said cam and actuatedthereby, the other lever contacting said pump operating element, androtation of `said cam causing movement of said pump operating element topump fuel to the engine, the quantity of fuel pumped by said fuel pumpbeing controlled by the position of said fulcrum member between saidlevers, and at least one of said levers having a stop member extendingtowards said other lever and being of such dimensions that said fulcrummember is substantially freed from contact with said levers for aninterval corresponding to a portion of the rotation cycle of said cam,and said ful- Crum member during said interval being freely movable bysaid pressure sensitive element so that small changes in intake manifoldpressure will affect the position of said fulcrum element.

6. A fuel injection system for an internal combustion engine having anintake manifold, said fuel injection systern comprising a rst and secondlever and a pump apparatus of the variable displacement type, means forcausing said first lever to oscillate with uniform amplitude in responseto the speed of sai-d engine, a fulcrum disposed between said first andsecond levers and being variable in its position, means associated withsaid engine and said fulcrum for altering the position of said fulcrumin response to changes in intake manifold pressure, said second leverdisposed to ybe substantially in contact with said fulcrum, said fulcrumbeing substantially in contact with said first lever and causing saidsecond lever to oscillate with varying amplitude according to changes inthe position of said fulcrum, a stop means associated with said secondlever to prevent effective contact between said fulcrum and said leversduring a portion of each cycle of operation, means associated with saidsecond lever and said pump apparatus for transmitting the variedoscillations of said second lever to said pump apparatus.

7. In a fuel injection system for an internal combustion engine, whichfuel injection system has a variable displacement pump, apparatus forvarying the stroke of the pump, said apparatus comprising a first andsecond lever, means associated with said first lever to cause said firstlever to oscillate with uniform amplitude, a fulcrum dis` posed betweensaid first and second lever, means associated with said fulcrum foraltering its position between said levers, said second lever disposed tobe substantially in contact with said fulcrum and caused by said fulcrumto oscillate with varying amplitude according to changes in the positionof said fulcrum, a stop means acting on said second lever to preventeffective contact between said fulcrum and said levers during a portionof each cycle, `and means for transmitting the varied oscillations ofsaid second lever to the variable displacement pump.

References Cited UNITED STATES PATENTS 1,726,303 8/1929 Knudsen123-139.2 2,562,656 7/1951 Blakeslee 123-l40.2 2,880,714 4/1959 Clark123-1403,

LAURENCE M. GOQDRIDGE, Primary Examiner.`

1. A FUEL PUMPING SYSTEM FOR AN INTERNAL COMBUSTION ENGINE HAVING ACRANKSHAFT AND AN INTAKE MANIFOLD, SAID SYSTEM COMPRISING A DIAPHRAGMTUPE FUEL PUMP ADAPTED FOR CONNECTION TO AN ENGINE AND HAVING A PUMPOPERATING ELEMENT, A PRESSURE SENSITIVE APPARATUS ADAPTED FOR CONNECTIONTO THE INTAKE MANIFOLD OF AN INTERNAL COMBUSTION ENGINE, SAID APPARATUSHAVING A DIAPHRAGM MOVABLE IN RESPONSE TO INTAKE MANIFOLD PRESSURE AND AFULCRUM ROD CONTACTING SAID DIAPHRAGM AND MOVABLE THEREBY, A CAM ADAPTEDFOR ROTATION IN RESPONSE TO ROTATION OF A CRANKSHAFT OF AN INTERNALCOMBUSTION ENGINE, A LINKAGE MEANS HAVING TWO LEVERS WITH SUBSTANTIALLYOPPOSITELY DISPOSED FULCRUMS, SAID LEVERS BEING DISPOSED SUBSTANTIALLYPARALLEL TO EACH OTHER, SAID FULCRUM ROD POSITIONED BETWEEN SAID LEVERSAND BY ITS POSITION AFFECTING THE AMOUNT OF MOVEMENT THAT ACTUATION OFONE LEVER IMPOSES UPON THE OTHER, ONE OF SAID LEVERS CONTACTING SAID CAMTO BE ACTUATED THEREBY AND THE OTHER LEVER CONTACTING SAID PUMPOPERATING ELEMENT, ROTATION OF SAID CAM CAUSING MOVEMENT OF SAID PUMPOPERATING ELEMENT TO PUMP FUEL TO THE ENGINE, THE QUANTITY OF FUELPUMPED BY SAID FUEL PUMP BEING CONTROLLED BY THE POSITION OF SAIDFULCRUM ROD BETWEEN SAID LEVERS, AND AT LEAST ONE OF SAID LEVERS HAVINGA STOP MEMBER EXTENDING TOWARDS SAID OTHER LEVER AND BEING OF SUCHDIMENSIONS THAT SAID FULCRUM ROD IS SUBSTANTIALLY FREED FROM CONTACTWITH SAID LEVERS FOR AN INTERVAL CORRESPONDING TO A PORTION OF THEROTATION OF SAID CAM, AND SAID FULCRUM ROD DURING SAID INTERVAL BEINGFREELY MOVABLE BY SAID DIAPHRAGM OF SAID PRESSURE SENSITIVE APPARATUS SOTHAT SMALL CHANGES IN INTAKE MANIFOLD PRESSURE WILL AFFECT THE POSITIONOF SAID FULCRUM ROD.